Precision welded metal bellows from Servometer are suited for applications where weight, strength, or flexibility is important. Assemblies with diameters as small as .187 inch and bellows with walls of .001 inch can be welded to a leak tightness of less than 1 x 10-9 cc He/sec. A wide variety of pressure, stroke, and stiffness combinations are possible. Pressures of 5000 PSI or higher can be accommodated by utilizing 3-ply bellows. Assemblies with low spring rates can be welded using variable wall thickness techniques. This capability minimizes the risk of damaging the thin, electrodeposited nickel bellows.